The Resonance EUV windowless source is an RF excited flow lamp with a capillary bore in an EMI shielded enclosure. This lamp mounts to a 33.78 mm or larger CF type flange.The lamp assembly has an integral RF exciter which is powered by a small wall plug power supply. This supply is sufficient to produce emissions from the principal neutral rare gas species in the range of 1015 photons per second per steradian. When coupled with a Resonance VM series monochromator, this will work as a tunable light source from 25 nm to up to 800 nm.